Xbox 360 has to update to play .avi?

I know the Xbox can play .avi files as I have done so before, but the only way for me to be able to play them is to keep repeatedly updating the Xbox with the same update to play the .avi

I put in my USB memory stick, go to "Portable Device" to play the files I want. I select the file and a message pop's up saying I have to update the xbox to play the file, so I sign into xbox live download the update and apply. Now i can watch the video's until I turn me xbox off, then if I decide to watch more later, when I turn it back it and try to play the .avi files the same message pop's up and I have to repeat. Is there any fix to this? or am I able to select the patch already downloaded to my xbox and re-apply or something 'without' signing back into live?

Also, would it be because the update is applied to my XBLA rather than my normal offline account which is what I try to play it on. I want to be able to play these files without being connected to the internet.